Plastic detergents and method of making same

ABSTRACT

Plastic detergent compositions suitable for use as shampoos comprise a sulphated or sulphonated anionic organic detergent and water (with or without an electrolyte) in sufficient amount to place the detergent system predominantly in the &#34;middle phase,&#34; the composition having a ready solubility in water and a plasticity such that it is adaptable to using out of a collapsable tube.  Anionic detergents of the above type, and mixtures of these with soaps, are said to form, with water, or water and electrolyte, phase systems having much the same behaviour as soap-water-electrolyte systems and in the Specification the terms &#34;neat phase,&#34; &#34;middle phase&#34; and &#34;nigre phase&#34; are applied equally to soap systems and to systems comprising synthetic detergents.  It is also stated that in the manufacture of ordinary soaps there is occasionally formed in the soap kettle, when too much water and too little electrolyte are present, an exceedingly viscous and gummy form of soap which is undesirable because it is immiscible with the other liquid phases present in the soap kettle and is very difficult to blend or convert into a more manageable form.  These so-called &#34;water lumps&#34; or &#34;gum soap&#34; are a distinct phase known as &#34;middle soap&#34; characterized by being relatively low in electrolyte content and intermediate in moisture content between the &#34;neat soap&#34; phase (typified by ordinary finished kettle soap in molten form) and the more watery &#34;nigre soap&#34; phase.  The existence of the detergent compositions of the invention in the pure middle phase region is said to be readily recognized by the rather tough gummy plasticity of the composition and its transparency.  It is also said to have a characteristic appearance when examined in thin films between crossed nicols under the microscope, as described in Jerome Aleander&#39;s &#34;Colloid Chemistry,&#34; Vol. I, 1926, p. 107.  The detergent composition may contain a water-soluble soap of higher fatty acids and the ratio of synthetic detergent to true soap may be between 9 : 1 and 1 : 9. The basic radicals of the detergents may comprise a substantial proportion of lower alkylolamines having the general formula R, R1, N.X.OH where X is any non-acidic organic residue containing not over 3 carbon atoms, and R and R1 may be hydrogen, any alkyl hydrocarbon radical containing not over six carbon atoms, or any non-acidic alcohol radical containing not over three carbon atoms.  Examples of such lower alkylolamines are the mono-, di-, and tri-ethanolamines and the corresponding normal- and iso-propanolamines, low molecular weight alkyl substituted derivatives such as methyl diethanolamine and dibutyl ethanolamine, mixed alkylolamines such as propanol diethanolamine, cyclohexyl ethanolamine, alkylol polyamines such as ethanol- and propanol-derivatives of ethylene diamine and 1, 2-diamino-propanol and 1-amino 2, 3-propanediol.  The anionic radical of the synthetic detergent may contain 8-26 carbon atoms and the detergent may include the salts of the sulphuric acid reaction products of aliphatic alcohols (e.g. the sodium salt of lauryl or oleyl sulphuric acid or of the sulphuric ester of higher alcohols derived by the reduction of coconut oil), of aliphatic hydrocarbons (e.g. the sodium salt of the sulphuric reaction product of hexadecene), of alkyl aromatic hydrocarbons and their derivatives (e.g. potassium salt of the sulphonic acid derived from the condensation product of benzene and a chlorinated kerosene fraction containing predominantly 12 carbon atoms per molecule), of mono-glycerides of higher fatty acids (e.g. the sodium salt of the coconut oil fatty acid mono-ester of 1, 2-dihydroxy-propane-3-sulphuric acid ester and of the corresponding sulphonic acid), of high molecular weight alcohol esters of low molecular weight carboxylic acids (e.g. the sodium salt of the lauryl ester of sulphonacetic acid), of mono-alkyl glycerol and glycol ethers (e.g. the monolauryl ether of the sodium salt of isethionic acid, the monomyristyl ether of the sodium salt of 1, 2-dihydroxy-propane-3-sulphonic acid, the monolauryl ether of the sodium salt of glycol monosulphuric acid and the triethanolamine salt of the coconut oil higher alcohol ether of 1, 2-dihydroxypropane-3-sulphonic acid), of high molecular weight acyl esters of glycol and diethylene glycol (e.g. the potassium salt of mono-oleoyl diethylene glycol sulphate and the coconut oil fatty acid ester of the sodium salt of isethionic acid), of high molecular weight fatty acid amides of lower molecular alkylolamines (e.g. the sodium salt of sulphated coconut oil fatty acid ethanol amide), of high molecular weight fatty acid amides of lower molecular alkyl amines (e.g. potassium salt of oleic acid amide of N-methyl taurine), and of low molecular weight carboxylic acid amides of alkylolamine esters of high molecular weight fatty acids (e.g. the sodium salt of the sulphoacetamide of amino ethyl laurate.  The synthetic detergents may also include lower alkylolamine and ammonium salts of sulphated and sulphonated detergents having unsaturated and/or relatively short (e.g. not over 12-14 carbon atoms) saturated hydrocarbon chains in their anionic radicals.  The detergent composition may contain a minor proportion of one or both of the more liquid phases, i.e. nigre phase and/or neat phase, dispersed throughout the middle phase.  At room temperature and in the substantial absence of electrolyte such as sodium chloride, sodium sulphate, sodium hydroxide, potassium chloride, sodium acetate, sodium phosphates and triethanolamine sulphate, chloride and acetate, the pure middle phase region of the anionic synthetic detergents and of mixtures of these with soaps is said in most cases to be found between about 40-50 per cent and about 85-90 per cent total detergent content, the remainder of the composition being water The water-soluble soap which may be present in the detergent composition may be potassium and lower alkylolamine oleates, linoleates, laurates and caprates; also potassium and lower alkylolamine soaps of the mixed fatty acids of oils of the coconut oil group (e.g. coconut, palm kernel and babassu).  Data are given for suitable ranges of synthetic detergent to soap weight ratios and approximate limits of total detergent content for the pure middle phase region in water-detergent systems containing specified synthetic detergents and soaps.  The total detergent content of the compositions of the invention is said to be usually more than 35 per cent and seldom over 80 per cent.  The compositions may contain finely divided titanium dioxide or zinc stearate or a crystalline solid such as stearic acid or glyceryl monostearate.  Modifying ingredients such as glycerin, ethanol, soluble cellulose derivatives or deodorized kerosine may also be added.  Free fatty alcohols such as mixed coconut oil alcohols may be added to the detergent to convert some of the middle phase to neat phase or alternatively free triethanolamine may be added to prevent the formation of the neat phase.  Electrolyte may be added to convert some of the middle phase to the nigre phase dispersed throughout the middle phase.  The soap, synthetic detergent and water components of the compositions may be mixed at elevated temperatures, e.g. 130-160 DEG F. at which the mass is in the nigre phase and then cooled to room temperature.  If the composition is undesirably firm, either water or electrolyte may be added very slowly with slow agitation until the desired consistency is reached.  In an example 20 parts by weight of triethanolamine salts of sulphated coconut oil fatty alcohol, containing 2 parts of trethanolamine sulphate and chloride and unsulphated fatty alcohols, 10 parts of triethanolamine oleate, 10 parts of triethanolamine coconut oil fatty acid soaps, 2 parts of glyceryl monostearate, 1 part of coconut oil free fatty alcohols and 55 parts of water are mixed at about 130-150 DEG F. and cooled to room temperature to form an opaque paste.  Other examples are given of the preparation by similar methods of detergent compositions of varying formulae including some in which all or part of the triethanolamine detergent salts and/or soaps are replaced by the corresponding sodium soaps. Methods are given for the recognition of the presence of neat phase or nigre phase in the compositions.

Jan. 1, 1952 R. c. WOOD 2,580,713

PLASTIC DETERGENTS AND METHOD OF MAKING SAME Filed Feb. 26, 1947 [18.15. IINVENTOR.

"M V MQ ATTORNEYS.

Patented Jan. 1, 1952 UNITED STATES PATENT OFFICE PLASTIC DETERGENT S' AND METHOD OF MAKING SAME Richard C. Wood, Westbury, N. Y., assignor to The Procter & Gamble Company, Cincinnati, Ohio, a corporation of Ohio Application February 26, 1947, Serial No. 731,148

31 Claims. 1

This invention relates to shampoos and other saponaceous detergents in non-liquid, non-solid, plastic form, suitable for packing and dispensing in collapsible tubes or in jars or tins.

Shampoos are detergents especially adapted for washing the hair and scalp, and are usually produced either in liquid form or in semi-liquid cream form, or in the form of an opaque paste.

I have discovered a shampoo (which is equally adaptable to other detergent uses) having a new and desirable physical form. It is normally a transparent or translucent, liquid-crystalline plastic composition having a surprising ease of solution when rubbed in the presence of water. It consists of highly soluble soap-like detergents in what is known as the middle phase, which may be somewhat modified and softened in consistency if desired by the inclusion of a minor proportion of a more liquid phase.

Soap-makers have long been familiar with.

so-called water lumpsi or gum soap which occasionally form in the soap kettle when too much water and too little electrolyte are present. Soap-boilers habitually take precautions to avoid this condition because this form of soap is so exceedingly viscous and gummy, and immiscible with the other liquid phases present in thesoap kettle, that it is very difiicult to blend or convert it into a more manageable form. These water lumps" are in reality a distinct soap phase which for about twenty years has been known as midrlle soap. This phase is relatively low in electrolyte content, and is intermediate in moisture con tent between the well known neat soap phase (typified by ordinary finished kettle soap in molten form) and the more watery "nigre soap phase, at correspondinglylow electrolyte content.

These three aqueous solution phases are mutually immiscible. v

The position of the middle soap region at different temperatures, for typical soap-water systems, is shown in Jour, Physical Chem, Nov. 1926, p. 1549, Fig. l, and in Colloid Chemistry by Jerome Alexander, vol. I, 1926, p. 142, Figs. 2 and 3.

The middle soap phase or sodium soaps of ordinary soap-making fatty acids; such as the fatty acids of ta llow, olive oil, and coconut oil, is stable only at elevated temperatures well above room temperature. Middle soap of the potassium salts of at least some of these same fatty acids can exist in stable condition at room temperature, and at this temperature it is a translucent tough gummy paste, in reality a comparatively firm plastic liquid crystal which dissolves in water with difficulty, even when rubbed. Soap in this form is commercially marketed in relatively small amounts, frequentlyas an automobile soap.

The detergent composition of my invention takes advantage of the plastic nature of the middle phase, and of its transparency when this is desired, yet avoids the excessive and objectionable toughness and slow solubility which has heretofore characterized this soap phase. My product, which possesses its desirable properties at room temperature, may by suitably adjusting its composition be made of varied degrees of plasticity and of solubility rate over comparatively wide ranges. Although normally transparent or translucent, my product may be made opaque if preferred.

I have found that compositions which essentially comprise suitable salts of soap-like anionic synthetic organic detergents (triethanolamine lauryl sulfate being a preferred and outstanding example), preferably in admixture with water-soluble soaps of higher fatty acids, may be brought into a middle phase which has the characteristic gumminess, although usually to a lesser extent, and the characteristic transparency of previously known middle soaps. These products have good water solubility and produce suds of desirable quantity, permanence, and cleansing power. A shampoo having outstanding advantages is produced from a mixture of soap and synthetic detergent predominantly in the middle phase, when a low molecular weight alkylolamine comprises at least the major proportion of the basic radicals.

My compositions produce an attractive and efiicient shampoo, or other detergent product, in paste form suitable for packing and distributing in collapsible tubes or shallow jars; produce such a product in a brilliantly transparent form, and having a smooth uniform texture; produce products of this character comprising synthetic soaplike detergents resistant to precipitation by constituents of hard water; produce a transparent soap shampoo containing effective hard-watercurd-dispersing detergents. I provide, furthermore, a shampoo in plastic form without having to resort to mixing a non-saponaceous thickening agent, or a solid saponaceous crystalline material, with detergents in liquid form (e. g. in the neat phase or nigre phase) as has been done in the past.

Examples of detergents in this new physical form made in accordance with this invention are as follows.

Example 1.--The following ingredients were blended by mild agitation at a temperature at which the mass remained highly fluid (i. e. in the nigre phase), about 130 F. to 150 F. 7

Parts Triethanolamine salts of lauryl sulfates, obtained by sulfating (with chlorsulfonic acid) the mixed fatty alcohols derived from coconut oil, and neutralizing these alkyl sulfuric acids with triethanolamine Triethanolamine oleate (from commercial oleic acid) 10 Triethanolamine mixed soaps of coconut oil 10 Commercial glyceryl monostearate, obtained by hydrogenating cottonseed oil to an iodine value of about 8 and esterifying with about two equivalents of glycerin 2 Lauryl alcohol, obtained from coconut oil by sodium reduction 1 TEA sulfate, TEA chloride, and nsulfated fatty alcohols, associated with the TEA alkyl sulfates approximately '2 Water, to bring to 100 parts.

When cooled to room temperature, after stopping the agitation, the product was an attractive opaque paste having a consistency of the same general order of that of slightly chilled petrolatum U. S..P. For commercial use it is usually desirable and customary to incorporate a minor amount of a water-soluble soap dye of desired hue and a small amount of perfume.

.In this composition the TEA alkyl sulfate is a highly soluble detergent which, is resistant to precipitation by hard water because its corresponding calcium and magnesium salts are Water soluble, and which is capable of existin in the middle soap phase .at ,room temperature. The TEA fatty acid soaps in this example are highly soluble soaps also capable of existing in the middle soap phase at room temperature. The glyceryl monostearate is included tomake the product opaque, and its omission results in an almost brilliantly transparent plastic product. The free fatty alcohol modifies and helps to stabilize the plasticity of the product. The electrolytes, TEA sulfate and chloride, make the consistency softer and the product more rapidly soluble than it would be in their absence. The

' softening of a given plastic detergent product, in

uted throughout the middle phase.

Example 2.Following a procedure similar to that of Example" 1, a somewhat -firmer plastic until all air bubbles escape, before allowing it to cool. The product may be softened in consistency, if desired, by adding small amounts of electrolytes, such as acetic acid or TEA acetate.

Example 3.--To 98.? parts by weight of a detergent paste containing 22% of TEA lauryl sulfate, 22% TEA coconut oil soap, about 2% of TEA chlorides and sulfates and Na chlorides and sulfates, about 2% of coconut oil alcohols, and and about 52% water, there were added one part of 56% acetic acid, one part of color solution, and 1.3 parts of water. This produced a rapidly soluble transparent plastic detergent which remained clear and homogeneous when stored for two months at a temperature of 120 F. and when stored for much longer periods Within the range of ordinary room temperatures.

Example 4.A plastic detergent generally similar to Examples 1 and 2 was made, containing 32% TEA lauryl sulfate and 14.5% TEA olive oil soap.

Similar desirable plastic detergent products, combining the'hard water curd dispersing propertiesof the synthetic detergents with the rich and stable lathering properties and economies of fatty acid soap detergents, were made containing amounts of total. synthetic detergent and soap varying from 40% to 60% by weight, and having ratios of synthetic detergent to soap varying from :25 to 25:75. The consistencies of these may be adjusted to desired values by means such as those described under Examples 1 and 2. The results obtained with these compositions indicated acceptable ranges in proportions considerably beyond those actually employed.

Following my discoveries of this new type of detergent product and this new form of shampoo, investigations were made to determine the range of different detergent components suiable for use in its preparation; to determine convenient means of identifying products of the invention and of distinguishing them from other detergent products in plastic or pasty or viscous form; and to establish an adequate understanding of the physical chemistry of the phases dealt with in the practice of the invention. a

It has been found that the ratio of synthetic detergent to true soap may vary considerably, depending upon critical phase relationships hereinafter discussed; but aside from such considerations ratios between :10 and 10:90 are preferred, not only for the sake of obtaining a product having desirable physical characteristics but also for obtaining at least a fair degree of hardwater-curd dispersion when used to wash the hair in hard water, and also for the sake of a rich and lasting lather when washing the hair. In the case of many synthetic detergents, particularly when present in the form of triethanolamine salts, the soap may be omitted from the formula entirely, if desired.

As the basicradicals forthe mixture of detergents a substantialproportion of ,a low molecular Weight alkylolamine is preferred, and in addition sodium and/or potassium and, if the soap content is low and hence the pH relatively close to'l.

ammonium may be employed. Alkylolamines suitable for this purpose, referred to herein as "lower alkylolamines, include the mono-, di-, and triethanolamine and the corresponding normaland iso-propanolamines, low molecular alkyl.

substituted derivatives such as methyl diethanolamine and dibutyl ethanolamine, mixed alkylolamines such as propanol diethanolamine, cyclohexyl ethanolamine, alkylol polyaminessuch as ethanoland propanolderivatives of ethylene diamlne and 1,2-diaminopropanol, l-amino 2,3- propanediol and other alkylolamines having equivalent behavior, also mixtures of any of the foregoing. This class of amines may be characterized as those having the formula R-NXOH where X is any non-acidic organic residue containing not over 3 carbon atoms, and R and R may be hydrogen, any hydrocarbon radical containing not over 6 carbon atoms, or any nonacidic alcohol radical containing not over 3 carbon atoms.

The anionic radical of the synthetic detergent may be any organic sulfate or sulfonate whose water-soluble salts have pronounced detergent action in water. These detergents constitute a large group of chemical compounds (the anionic radicals of which usually contain between 8 and about 26 carbon atoms) which includes such substances as salts of the sulfuric reaction products of aliphatic alcohols (e. g. sodium salt of lauryl or oleyl sulfuric acid or of the sulfuric acid ester of higher alcohols derived by the reduction of coconut oil), of aliphatic hydrocarbons (e. g. sodium salt of the sulfuric reaction product of hexadecene), of alkyl aromatic hydrocarbons and their derivatives (e. g. potassium salt of the sulfonic acid derived from the condensationprodnot of benzene and a chlorinated kerosene fraction containing predominantly 12 carbon atoms per molecule), of monoglycerides of higher fatty acids (e. g. sodium salt of the coconut oil fatty acid mono-ester of 1,2-dihydroxy-propane-3- sulfuric acid ester and of the corresponding sulfonic acid), of high molecular alcohol esters of low molecular carboxylic acids (e. .g. the sodium salt of the lauryl ester of sulfoacetic acid), of monoalkyl glycerol and glycol ethers (e. g. monolauryl ether of the sodium salt of isethionic acid, the monomyristyl ether of the sodium salt of 1,2- dihydroxy-propane-3-sulfonic acid, the monolauryl ether of the sodium salt of glycol monosulfuric acid, and the triethanolamine salt of the coconut oil higher alcohol ether of 1,2-dihydroxy propane-3-sulfuric acid), of high molecular acyl esters of glycol and diethylene glycol (e. g. the potassium salt of monooleoyl diethylene glycol sulfate and the coconut oil fatty acid ester of the sodium salt of isethionic acid), of high molecular fatty acid amides of lower molecular alkylolamines (e. g. sodium salt of. sulfated coconut oil fatty acid ethanol amide), of high molecular fatty acid amides of lower molecular alkyl amines (e. g. potassium salt of oleic acid amide of N-methyl taurine), of low molecular carboxylic acid amides of alkylolamine esters of high molecular fatty acids (e. g. sodium salt of the sulfoacetamide of amino ethyl laurate), and the like. All of the numerous anionic synthetic organic sulfate and sulfonate detergents having good detergent properties which have been tested have been found to be capable of assuming the middle soap phase, either alone or if not alone 6 (depending largely on the basic radical) then'in admixture with suitably chosen soaps, as hereinafter explained, "and none are known which would not be expected to be suitable for use in the present invention.

This group of anionic synthetic detergents, and mixtures of these with soaps, form, with water and electrolyte, phase systems having much the same behavior as soap-water-electrolyte systems, although each different system has its own phase boundaries. The terms neat phase, middle phase and nigre phase are used in this speciflcation as equally applicable to soap systems and to systems comprising synthetic detergents.

The consistency of products of the invention at room temperature, which is conveniently measured and recorded in terms of a standardized penetration test, such as that described in the U. S. Pharmacopaea for testing petrolatum, may be varied over a wide range by choice of the basic radicals and also by formulating the composition so that it contains, if desired, a minor proportion of one of the more liquid soap phases, e. g. nigre soap phase and/or neat soap phase. Thus, increasing the proportion of sodium salts of the detergent components tends to increase the firmness or body of the composition, whereas increasing the proportion of alkylolamine saltsof the detergents has the reverse tendency. The composition may conveniently be made to contain a small amount of the detergent ingredients in the nigre phase, dispersed throughout the middle phase, either by increasing the moisture content or by increasing the electrolyte content, or by simultaneously increasing both of these, beyond the values at which the composition is in the pure middle phase. The addition of free fatty alcohol tends to convert some of the middle phase to neat phase, and the addition of small amounts of free triethanolamine tends to avoid the formation of the neat phase. The transparency of the composition is aifected but slightly by the presence of dispersed nigre phase (which has nearly the same refractive index as the corresponding middle phase), but the presence of neat phase causes noticeable turbidity or cloudiness.

The investigations above referred to provided basis for many additional examples, of which the following are typical:

Example 5.A quantity of mixed higher :alcohols obtained by sodium reduction of coconut oil was sulfated with chlorsulfonic acid. The resulting lauryl sulfuric acid mix was neutralized with an equimolecular mixture of TEA and aqueous sodium hydroxide, and a sufficient additional amount of this alkaline mixture was added to react with'the mixed coconut oil fatty acids which were added as soon as the neutralized alkyl sulfate paste had been heated to about 160 F Small amounts of coloring matter, perfume, b01- rax, sodiumtripolyphosphate, and a slight excess of TEA, were added, together with enough water to bring the total watercontent of the mass up to 50%. The consistency of the mass was then adjusted to the desired valuesuitable for use from a collapsible tube, judged by a sample cooled to room temperature, by adding small amounts of acetic acid or coconut oil alcohols (to soften the consistency), or by adding a small amount of TEA (to increase the firmness). After stirring a few minutes, and allowing to cool quietly to about F., the liquid material was filled into tubes which were sealed and allowed to cool. The product was a transparent medium soft plastic.

7 containing a minor amount of nigre phase throughout the main body of middle phase. 7 The amounts of materials used were such that (without allowing for double decomposition shifts in the organic Na and TEA salts) the product consisted of:

( /2 mol Na, /2 mol TEA) lauryl TEA chloride, sulfate,

and acetate Na chloride, sulfate,

and acetate 1 percent, approx 2.3

The components of the Examples 6 to 10 were essentially synthetic detergent-soap-water, with only minor amounts of extraneous materials which were associated with the synthetic detergent. The compositions of these detergents were as follows:

Sodium monoglyceride sulfonate, made from mixed fatty acids from coconut oil. The sulfonate was about 99% pure, the remainder being about 1% water, under 0.1% unsulfonated, and traces of NaCl and Na2SO4.

Sodium monoglyceride sulfate, made from coconut oil fatty alcohols. Desalted commercial Vel was used, about 99% pure detergent sulfate, about 1% water, under 0.1% unsulfated, trace of Na2SO4.

Sodium alkyl benzene sulfonate, made from monoalkyl benzene averaging about 11 to 12 carbon atoms in the alkyl chain. Desalted Santomerse 3 was used, about 96.6% pure sulfonate, 3% water, 1.34% unsulfonated, trace Na2SO4.

Sodium sulfoacetic ethanolamide laurate, the laurate group being mixed coconut oil fatty alcohols. This detergent was about 96% pure, the remainder being about 1% water, under 0.1% petroleum ether extract, 2.8 NaCl, trace NazSO4.

Sodium lauryl sulfoacetate, the lauryl" group being mixed coconut oil fatty alcohols. Desalted Nacconol LA was used, about 99% pure, and containing 0.3% NaCl and traces of water and NazSOa.

In each of Examples 6 to 10 the designated synthetic detergent was mixed with substantially pure TEA (triethanolamine) coconut oil soap and water in the proportions required to produce the finished product analysis shown in the examples, the percentage figures shown therein representing the pure materials. It is of course understood that in all cases double decomposition exchanges of radicals may occur; thus in Example 6, the Na sulfonate and TEA soap interact to some extent to form Na soap and TEA sulfonate.

In each case the mixture was warmed to about 250 F. in a closed container, stirred to make it homogeneous, and cooled quickly to room temperature.

Example 6 Na monoglyceride sulfonate percent 7.5

TEA coconut oil soap do 50.0

Water do 42.5

Minor extraneous materials Trace 8 The product had a relatively stiff consistency and was in the middle phase.

Example 7 Na monoglyceride sulfate percent 5.0 TEA coconut oil soap do 45.0 Water, do 50.0 Minor extraneous materials Trace The product had a relatively soft consistency and contained a small amount of nigre Phase uniformly dispersed in the main body of middle phase.

Example 8 Percent Na alkyl benzene sulfonate 24.0 TEA coconut oil soap 25.0 Water 50.7 Minor extraneousmaterials 0.3

The product had a relatively stilT consistency and was in the middle phase.

Example 9 Percent Na sulfoacetic ethanolamide laurate 9.6 TEA coconut oil soap 45.0 Water 45.1 Minor extraneous materials 0.3

The product had a relatively stiff consistency and was in the middle phase.

Example 10 Na lauryl sulfqacetate percent 10.0 TEA coconut oil soap do 70.0 Water do 20.0 Minor extraneous materials Trace Water 50.5

Coconut oil alcohols 5.1

Minor extraneous materials (Na, TEA, chlorides and sulfates) 1.0

Example 12.-F0llowing the same procedure as in Examples 6 to 10, an all middle phase synthetic detergent product having a medium plastic consistency was made with the following formula:

Percent TEA lauryl sulfate 60.0 Water 29.9 (TEA) 2804 7 .1 TEA-Cl 0.7

Coconut oil alcohols and minor extraneous materials 2.3

Example 13.--Following the same procedure as in Examples 6 to 10, an all middle phase product having a medium heavy plastic consistency was made with the following formula:

Percent TEA lauryl sulfate 18.4 TEA oleate 22.4 Water 56.1 (TEA) 2504 2.2 TEA-Cl 0.2

Coconut oil alcohols and minor extraneous materials 0.7

At room temperature and in the substantial absence of electrolytes such as sodium chloride, sodium sulfate, sodium hydroxide, potassium chloride, sodium acetate, sodium phosp triethanolamine sulfate, chloride and acetate, and the like, the pure midcliephase region of the anionic synthetic detergents and of soap-synthetic detergent mixtures is in most cases to be found between about 4-9 or 59 per cent about 8-501 90 per total detergent content. existence of the composition in this region is readily recognized by its rather tough gummy plasticity and its substantially clear translucency or transparency. Further and more positive confirmation of the presence of the middle phase, if desired, may be obtanied by microscopic examination of a thin layer of the material between crossed nicol prisms. Middle phase can be distinguishcd from other known detergent phases which might be present viscous or plastic or paste type detergent composition at room tom pcrature by a certain characteristic conic or smcctic anisotropic liquid crystalline nature (a class of liquid crystals described in Jerome Alexanders Colloid Chemistry, vol. I, 1926, beginning p. 107) as illustrated by the accompanying photographs. Figure l of the annexed drawings is a reproduction a phctomicrograph (100 diameters) of a sample of the product of Example as observed between crossed nicols soon after the material was pressed out under a coverglass on a microscope slide, and is characteristic of mid.- dle phase material as distinguished from neat and nigre. Figure 2 illustrates the same microscope slide (sealed around the edges to prevent moisture loss) about 5 hours later, after the liquid crystals havesubstantially reformed so as to display their conic'nature. Both views are fairly typical of products of the presentinvention at room temperature. r I

The presence of relatively small. amounts of nigre phase admixed with the middle phase in products of the invention is most conveniently judged by the sharp drop in the viscosity of the mass which occurs when nigre phase is first introduced, together with the absence of evidence of neat phase as later explained. .Small amounts of nigre phase dispersed throughout middle phase change the product from a rather tough gum, resembling cold Vaseline or heavy lubricating grease in consistency, to a. softer plastic having a consistency much like that of medicinal Vaseline at room temperature. Larger amounts of nigre phase in the product may make it undesirably soft and subject to separation of phases. Under .a polarizing microscope masses of nigre phase ordinarily remain dark in the field, since this phase is an isotropic or microscopically amorphous liquid. Exceptionally viscous nigres mayshow a brightening of the field when disturbed, but show no microscopicv structure as do middle and neat phases. g The presence of neat phase ln room temperature samples of detergent compositions can be judgedv in several ways. Neat phase, although not; an ordinary liquid' (since, for example, unsupported drops do not assume a spherical shape), has a very much softer or more liquid consistency than middle phase, but is more viscous than nlgre phase. 'Neat phase is an anlsoreproduction-of a photom-icrograph (100 diam eters) ofa sample of hydrated potassium soap of commercial oleic acid (70% soap, 30% water), in the neat phase and Fig. 4 illustrates thelsame microscope field taken just after pressing the cover glass down on the sample. It is to be noted that areas which are black. in Fig. 3 have become; bright in Fig. 4. The structures illustrated in these photographs and. the behavior when disturbed, an effect which is often rapidly reversible in sufiiciently fluid neat phase, serve to distin-- guish neat phase from middle phase. Droplets of neat phase dispersed in middle phase may also be recognized by their paler color when the product is artificially colored, because neat phase is. a poorer solvent for water-soluble colors than is middle phase.

From what has been said it will be understood that saponaceous detergents, comprising anionic synthetic detergents, which one may use in the present invention include a large group of individual detergent species and mixtures of species, Those which one may expect to be capable of existing in a middle phase stable at room temperature, and which are therefore suitable for use, include (without limiting the invention to these): potassium and lower alkylolamine oleates, linoleates, laurates, caprates; potassium and lower alkylolamine soaps of the mixed fatty acids of oils of the coconut oil groupv (coconut, palm kernel, babassu, and the like) lower alkylolamine and ammonium sulfateand sulfonatedetergents having unsaturated. and/ or relatively short (e. g. not over 12 to 14 carbon atoms) saturated hydrocarbon chains in their anionic radicals; also mixtures of major proportions of any one or more of the foregoing Witl minor proportions of any one ormore of the following: sodium, potassium, lithium, and lower alkylol amine salts of any soap-making organic acid and of any anionic organic sulfateor sulfonatedetergent. I I

The room'temperaturepure middle phase re gion for any such detergent or mixture of detergents, in the substantial absence of electrolyte, includes in nearly all cases detergentzwater ratios somewhere between :40 and :30; thus providing a convenient starting point in locating and plotting the middle phase field with any unfamiliar detergent mixture. Having selected a suitable moisture content for any appropriately chosen mixture of soap and synthetic deter-1 gents within the pure middle phase region, the

boundaries of this region on the side towards the adjacent middle-nigre region may be determined by adding either water or electrolyte very slowly with slow agitation and noting when a sudden softening of consistency occurs. If for the given formula the composition is undesirably firm in the pure middle phase region, this addition of water or electrolyte maybe continueduntil the desired consistency is reached. In order to facilitate easy mixingsuch adjustments are made at an elevated temperature, often between F. and

11 of the middle phase region it is understood that it means free from other detergent phases to the extent that this can be judged by known methods of the character previously described.

The following table is a rough guide to show the approximate range of proportions of typical pairs of phase and synthetic detergent which may be used in formulating products of the invention, and to show the approximate detergentzwater ratios of the extreme limits of the pure middle phase region for each of these pairs:

ready solubility in water, comprising: mixing saponaceous detergent, at least per cent of which is a sulfated or sulfonated anionic organic detergent, water amounting to at least 10% and not more than of the total composition, and electrolyte to form a highly fluid homogeneous mass in the nigre phase, having an elevated temperature above that at which a second detergent phase forms, and cooling said mass to room temperature, the composition of said mass being such that at room temperature it is pre- Mixtures of the following Approximate lllgiis 0i tottal e ergen asses es 333 thetic detergent gggg g g Synthetic Detergents 1 Soap to soap in watep detergent system Per cent Na monoglyceride sulfonate TE ik coconut 24:76 to 10= 90 50 to 85 or soap. Na monoglyceride sulfate 27:73 to 10z 00 50 to 85 Na alkyl benzene sulfonate 55:45 to l0: 90 to 85 Na sulfoacetic ethanclamide 21:79 to 10: 90 to 85 laurate. Na lauryl sulfoacetate Sa e 27 :73 to 10: 90 to 85 04 mol Na, 36 mol TEA) alkyl 74:26 to l0: 90 40 to sulfate.

coconut oil soap. TEA alkyl sulfate TE iA coconut 100:0 to l0z 90 55 to Ol soap. TEA alkyl sulfate TEA oleate... :0 to l0: 90 65 to 75 1 These synthetic detergents, which are the same as those used in Examples 6 to 10 were associated with small amounts of impurities as explained in connection with these examples. The soap was substantially pure and anhydrous.

I These are weight ratios, "as is" basis. 3 These are weight percentages, "as is basis. ages shown and 100% represent the water added.

Nearly every ingredient which is added to the formula has the effect of shifting the phase boundaries, and for this reason it is desirable to incorporate all desired ingredients (coloring matter, perfume, preservative, for example), with the possible exception of some free triethanolamine and/or electrolyte, before finally adjusting these latter ingredients so as to obtain a product either in the pure middle region, or in the mixed middle-nigre region, as desired. A good degree of chemical stability is desired in all components of the shampoo, in order that no appreciable phase changes will gradually be caused by the formation of decomposition products.

The total active detergent content of products of the invention is usually more than 35 per cent and is seldom over 80 per cent, depending upon choice of ingredients and desired consistency and ease of solution.

If an opaque plastic product is desired, rather than a translucent or transparent product, this result may be accomplished either by incorporating air in vesiculated form or by incorporating a finely dividedsolid material such as titanium dioxide or zinc stearate, or a crystalline solid such as stearic acid or glyceryl monostearate, any such crystalline materials preferably being incorporated at a temperature sufficiently high to bring it into a liquid condition in order that upon cooling and resolidifying it will appear as minute crystals which produce a desirable sheen in the paste. Modifying ingredients may be added for various other purposes if desired, such as glycerin, ethanol, soluble cellulose derivatives, deodorized kerosene, to name but a few.

Having thus described my invention, what I claim and desire to obtain by Letters Patent is:

1. The process of preparing a detergent composition having a soft plastic consistency and a The differences between the percentdominantly in the middle phase but includes a minor proportion remaining in the nigre phase, said middle phase having a gummy plasticity and a characteristic conic anisotropic liquid crystalline nature as observed under a polarizing microscope, and said nigre phase being characterized by its amorphous nature and lack of structure as observed under a polarizing microscope, the amount of said nigre phase in the composition at room temperature being sufilcient to impart to said composition ready solubility in water and reduced toughness and being not so great as to cause separation of phases.

2. The process of claim 1, in which the consistency of the product is adjusted to the desired softness by adding small amounts of electrolyte to the mass while in the nigre phase at the elevated temperature. 5-5 3. The process of preparing a detergent composition having a soft plastic consistency and a. ready solubility in water, comprising: mixing at a temperature of about to about F. a saponaceous detergent (at least 25 per cent of which is a sulfated or sulfonated anionic organic detergent), at least about 10% water, and electrolyte, to form a highly fluid homogeneous mass in the nigre phase, containing between 35 per cent and 80 per cent of saponaceous detergent ingredients, and cooling said mass to room temperature, its composition beingso chosen that at room temperature it is predominantly in the middle phase but includes a minor proportion remaining in the nigre phase, said middle phase having a gummy plasticity and a characteristic conic anisotropic liquid crystalline nature as observed under a polarizing microscope, and said nigre phase being characterized by its amorphous nature and lack of structure as observed under 75 a polarizing microscope.

4. The process of preparing a detergent composition having a soft plastic consistency and ready solubility in water, comprising: mixing at a temperature of about 130 F. to about 160 F. a saponaceous detergent (at least per cent of which is a sulfated or sulfonated anionic detergent), at least about 10% water, and electrolyte, to form a fluid homogeneous mass containing between per cent and 85 per-cent of saponaceous detergent ingredients; and cooling said mass to room temperature thereby converting it predominantly to the middle phase, having a gummy plasticity and a characteristic conic anisotropic liquid crystalline nature as observed under a polarizing microscope, the relative proportions of saponaceous detergent, water, and electrolyte of the original mixture being so chosen with regard to the character of the detergent and the electrolyte that the-final composition at room temperature includes a minor proportion of detergent in a liquid detergent phase.

5. As a new article of manufacture, a detergent composition comprising as an essential ingredient a sulfated or sulfonated anionic organic detergent, more than 35% but not more than 90% of the said composition being saponaceous detergents selected from the group consisting of water-soluble soaps and sulfated or sulfonated anionic organic detergents, and at least 10% of said composition being water, the said sulfated or sulfonated detergents amounting to from 10% to 100% of the total of said saponaceous detergents, all saponaceous detergent components of said composition being predominantly and stably in the plastic and substantially transparent middle phase at room temperatures as'detectable by microscopic observation, said composition comprising also a dispersion of a minor proportion of a phase of said detergent components that is more liquid than said middle phase, said composition thereby having a rate of solution in water greater than and a plastic consistency softer than the corresponding values of potassium middle soaps of commerce and of the detergent components of the said composition when entirely in the homogeneous middle phase at room temperature.

6, The composition of claim 5 in which the greater solution rate and softer plasticity are due to the presence of increased electrolyte components, in relation to the water content of the composition, as compared with otherwise identical compositions entirely in the homogeneous middle phase at room temperature.

'7. The composition of claim 5 in which the greater solution rate and softer consistency are due to the presence of detectable minor amounts of the liquid nigre phase of the detergent components, uniformly dispersed throughout the said middle phase.

8. The composition of claim 5, comprising also amounts of electrolytes of the group consisting of acetic acid, and acetates, chlorides and sulfates of sodium, potassium, ammonium, and lower alkylolamines, sufficient to prevent the detergent components of said composition from being entirely in the middle phase.

9. As a new article of manufacture adaptable for use as a shampoo, a perfume-containing and translucent to substantially transparent detergent composition in rapidly soluble soft plastic form at room temperatures, having an extremely smooth texture and being free from the objectionable tough gumminess and slow solubility which characterizes prior middle phase detergents, and being easily dispensable from a collapsible tube upon the application of slight pressure, said composition comprising as an essential ingredient a sulfatedor sulfonated anionic organic detergent, all detergent components of said composition being chosen from the group consisting of fatty acid soaps .and sulfated and sulfonated anionic detergents, more than 35%but not more than of said composition being said detergent components, said detergent components being predominantly and stably in the middle phase at room temperature as detectable by microscopic observation, a substantial proportion of said detergent components, and enough to increase the solution rate and increase the softness of said composition, being lower alkylol amine'detergent salts.

10. The detergent composition of claim 9, ren dered opaqueby' the presence of an opacifying agent in'fi-nely divided form uniformly dispersed the'rethrough.

11. The composition of claim 9, comprising a substantial proportion of lower alkylolamine detergent salts.

12. The composition of'claim 9, wherein'the detergent components comprise a substantial proportion of sodium detergent salts.

13. The composition of claim 9, comprising water-soluble soap in a substantial amount which does not exceed 96% of the total of the detergent components of said composition.

14. The composition of claim 9, including in intimate admixture with said middle phase a minor propoition of a phase of the detergent components more liquid than said middle phase, the amount of said more liquid phase being sumcient to impart to said composition ready solubility in water and reduced toughness, an'd'being not so great as to cause separation of phases.

15. rhe composition of claim 14, in which said more liquid phase is the liquid nigre phase.

16. The composition of claim 15, comprising triethanolamine detergents selected from the group consisting of triethanolamine soaps of coconut oil fatty acids and triethanolamine sulfates of fatty alcohols derived from coconut oil, and'mixtures thereof.

17. The composition of claim 15, in which the totaldetergent content is between 40 per cent and 60 per cent by weight.-

18. As a new article'of manufacture, a detergent composition in plastic and translucent to substantially transparent form, comprising a sulfated or sulfonated anionic organic detergent, at least about 10% and not more than 40% water, and a water soluble soap amounting to at least 35% of said composition, said detergent and soap being predominantly and stably in homogeneous middle phase at room temperatures as detectable by microscopic observation, and said organic detergent being at least 10% of the total of said detergent and said soap.

19. The composition of claim 18, rendered opaque by the presence of an opacifying agent in finely divided form uniformly dispersed therethrough.

20. The composition of claim 18, in which substantial amounts of the basic radicals of said detergent and soap are those of a lower alkylolamine.

21. The composition of claim 20, in which the lower alkylolamine is triethanolamine.

22. The composition of claim 18, in which substantial amounts of the basic radicals of said detergent and said soap are those of sodium.

23. The composition of claim 18, comprising also in intimate admixture therewith a minor proportion of a phase of said detergent and soap more liquid than said middle phase, the amount of said more liquid phase being sufficient to impart to said composition ready solubility in water and reduced toughness, and being not so great as to cause separation of phases.

24. The composition of claim 23, in which said more liquid phase is the liquid nigre phase.

25. A translucent to substantially transparent detergent composition of soft plastic consistency and ready solubility in water, comprising 40 per cent to 60 per cent by weight of a mixture of different saponaceous detergents at least one fourth of which are lower alkylolamine organic sulfate or sulfonate detergents, and which at room temperatures under a polarizing microscope exhibits a characteristic anisotropic liquid crystalline nature and which upon heating to about 130 F. to 250 F'., under sufficient pressure to prevent boiling, loses its liquid crystalline nature and becomes an isotropic liquid.

26. As a new article of manufacture, a detergent composition having a soft plastic consistency suitable for its packaging in collapsible tubes and in jars, comprising from 40 per cent to 60 per cent by weight of water-soluble fatty acid soap and soap-like synthetic sulfate or sulfonate detergent, the ratio of soap to synthetic detergent ranging from 75:25 to 25:75, and at least about water, the composition comprising an amount of the homogeneous middle phase (of all detergent components thereof sufficient to impart substantial plastic body, at least half of the basic radicals being those of triethanolamine.

27. The composition of claim 26, comprising also a small amount of a consistency modifying agent chosen from a group of electrolytes consisting of acetic acid and triethanolamine acetate.

28. A composition of claim 26, comprising also a small amount of free fatty alcohol as a consistency modifying agent.

29. As a new composition of manufacture, a synthetic detergent-containing composition in a rapidly soluble soft plastic form, comprising at least one member of the group composed of sodium soaps and sodium anionic organic detergent sulfates and sulfonates which in admixture with water and electrolyte are capable of existing stably in the middle phase only at elevated temperatures above room temperature in the absence of other detergents, and comprising also at least one member of the group consisting of potassium, ammonium, and lower alkylolamine soaps and ammonium and lower alkylolamine anionic organic detergent sulfates and sulfonates which in admixture with water and electrolyte are capable of existing stably in the middle phase at room temperature, the proportion by weight of detergent components of the second group being greater than the proportion of detergent components of the first group, all detergent compoents of said composition being predominantly and stably in homogeneous middle phase at room temperatures as detectable by microscopic observation, said composition containing at least about 10% water, and the total amount of detergent sulfates and sulfonates in said composition being at least 10% of the total of said soaps and said detergent sulfates and sulfonates.

30. The composition of claim 29, containing only liquid crystalline and isotropic liquid components and being free from components in solid form.

31. The composition of claim 29, including in intimate admixture with said middle phase a minor proportion of the liquid nigre phase of said detergent components, the amount of said nigre phase being sufficient to impart to said composition ready solubility in water and reduced toughness, and being not so great as to cause separation of phases.

RICHARD C. WOOD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,047,320 Ferguson July 4, 1936 2,134,666 Kritchevsky Oct. 25, 1938 2,345,307 Vitalis Mar. 28, 1944 OTHER REFERENCES Article, Phase Behavior of Dodecyl Sulphonic Acid and Its Alkali Salts with Water, Marjorie J. Vold, May 1941. 

1. THE PROCESS OF PREPARING A DETERGENT COMPOSITION HAVING A SOFT PLASTIC CONSISTENCY AND A READY SOLUBILITY IN WATER, COMPRISING: MIXING SAPONACEOUS DETERGENT, AT LEAST 25 PER CENT OF WHICH IS A SULFATED OR SULFONATED ANIONIC ORGANIC DETERGENT, WATER AMOUNTING TO AT LEAST 10% AND NOT MORE THAN 40% OF THE TOTAL COMPOSITION, AND ELECTROLYTE TO FORM A HIGHLY FLUID HOMOGENEOUS MASS IN THE NIGRE PHASE, HAVING AN ELEVATED TEMPERATURE ABOVE THAT AT WHICH A SECOND DETERGENT PHASE FORMS, AND COOLING SAID MASS TO ROOM TEMPERATURE, THE COMPOSITION OF SAID MASS BEING SUCH THAT AT ROOM TEMPERATURE IT IS PREDOMINANTLY IN THE MIDDLE PHASE BUT INCLUDES A MINOR PROPORTION REMAINING IN THE NIGRE PHASE, SAID MIDDLE PHASE HAVING A GUMMY PLASTICITY AND A CHARACTERISTIC CONIC ANISOTROPIC LIQUID CRYSTALLINE NATURE AS OBSERVED UNDER A POLARIZING MICROSCOPE, AND SAID NIGRE PHASE BEING CHARACTERIZED BY ITS AMORPHOUS NATURE AND LACK OF STRUCTURE AS OBSERVED UNDER A POLARIZING MICROSCOPE, THE AMOUNT OF SAID NIGRE PHASE IN THE COMPOSITION AT ROOM TEMPERATURE BEING SUFFICIENT TO IMPART TO SAID COMPOSITION READY SOLUBILITY IN WATER AND REDUCED TOUGHNESS AND BEING NOT SO GREAT AS TO CAUSE SEPARATION OF PHASES. 